I always get mine early too. I live in PA. your zone. I put them into a tub
of pond water and if there is sun for the day I put them out--I only bring
them inside if the temps are dropping below 50 for the night. Next week the
temps for you will go up alot more and keeping them in a separate container
in the sun will also warm the water they are in. After it warms up in the
pond I transfer them into a laundry basket and place them on the pond edge
so they can multiply without the koi eating them up to fast.
Patty